Mineral oil products



Patented Nov. 1, 1938 MINERAL OIL PRODUCTS Robert L. Sibley, Nitro, W. Va., assignor, by mesne assignments, to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware No Drawing. Application February 3, 1934, v

i Serial N0. 709,591

Claims.

This invention relates to improvement in means for the protection of liquid hydrocarbon products against discoloration and formation of insoluble and gummy products. More particularly the 5 presentinvention relates to improved materials for: use with liquid hydrocarbons which may be used as fuels.

Liquid hydrocarbons as commercially produced,

particularly when prepared by the distillation or cracking of petroleum, possess a tendency to discolor on standing and to form gums and resinous substances. Gasolines produced by the modern cracking processes are extremely complicated mixtures comprising many constituents, the character of these constituents and the relative proportions of the different constituents depending upon the source of the crude and the particular cracking process employed. Among other constituents, the crude cracked gasoline contains un- 20 saturated hydrocarbons, such as for example the olefines and diolefines. The more recent pressure methods of vapor phase cracking result in a considerably higher percentage of diolefines than the older methods. It has thus become necessary to treat the crude products resulting from the more recent cracking processes in some manner to remove the greater part, of these morehighly unsaturated products. Among these methods of treatment may be mentioned the. sulfuric acid treatment and the fullers earth vapor phase treatment. While these methods "of purification have certain advantages and may remove the greater part of the highly unsaturated compounds, it is still found that many petroleum distillates, for example gasoline and kerosene, become discolored and develop a quantity of gummy materials during storage.

This discoloration developed in gasoline, kerosene and the like is objectionable to consumers and distributors of these products and the-presence of gummy material in gasoline causes such undesirable eifects, when used in internal combustion engines as sticking of the valve stems and excessive carbon formation.

In accordance with this invention the development .of these undesirable characteristics in petroleum products may be readily prevented or materially delayed without apparently increasing the cost of production thereof.

i The present invention has for an object the inhibition of the formation of gums and resins in oil compositions.

Another object of the present-invention is to provide a new mineral oil product possessing improved properties particularly for use as a fuel for internal combustion engines. The treating means and special compositions disclosed herein are likewise adaptable for'use as a transformer oil, as a lubricating means, as a heat circulating medium and analogous uses wherein it isdesirable that an improved and satisfactory stable mineral oil product be employed.

Another object of this invention is to provide a method of and means for preventingor materially decreasing the development of discoloration in petroleum distillate products.

Another object is to provide a method and means of the character referred to that will not appreciably increase the cost of production of petroleum products.

Other objects of the invention will beapparent from'the following description.

The class of materials which have been found to possess the desirable qualities set forth in that small proportions thereof when incorporated in a relatively unstable oil product, for example gasoline and kerosene, materially increases the stability thereof, comprise compounds possessing the structural formula of -coox -coox where R is an aromatic radical and X is hydrogen or a salt forming element or salt forming radical.

Illustrative of the preferred class of materials and included within the scope of the present invention are the following materials: phthalic acid, sodium phthalate, sodium acid phthalate, diphenyl guanidine phthalate, diphenyl guanidine acid phthalate, aniline acid phthalate, hexamethylenetetramine acid phthalate, para amino phenol acid salt of phthalic acid and the para phenetidine acid salt ofphthalic acid. Diphenyl guanidine phthalate, dlphenyl guanidine acid phthalate, aniline acid phthalate, hexamethylenetetramine'acid phthalate, para amino phenol acid salt of phthalic acid and the para phenetidine acid salt of phthalic acid may be assigned the following formulae.

Diphenyl guanidine phthalate I Diphenyl guanidine acid phthalate a )Q C 0H.HN=C

O Aniline acid phthalate coonmNQ CODE Hexamethylerietetramine acid phthalate o 0 0 H. c QHBNA COOH Para amino phenol acid salt of phthalic acid coonrnnO-OH COOH . Para phenetidine acid salt of phthalic acid ooonlmnOo can coon As as specific embodiment of the present invention but not a limitation of the scope thereof 10 mgs. of diphenyl guanidine phthalate were dissolved in 100 c. c. of an unstable gasoline, for example a cracking coil distillate, and exposed to northern light for six days together with a sample of the same untreated gasoline. At the endof this period of time the two samples were compared as to color in a suitable apparatus, and it was found that, while the gasoline containing one of the preferred class of materials, for example diphenyl guanidine phthalate, had undergone substantially no change in color, the untreated gasoline showed a yellowing in color. On continuing the test for a total of thirty days, the gasoline containing diphenyl guanidine phthalate had undergone substantially no change in color,

whereas the untreated gasoline had a decided yellow color.

As another specific embodiment of the present invention, 10 mgs. of hexamethylenetetramine acid phthalate were dissolved in 100 c. c. of an unstable gasoline, for example a cracking -coil distillate, and together with a sample of the untreated gasoline exposed to northern light for thirty days.

the gasoline containing one of the preferred class of materials, for example hexamethylenetetramine acid phthalate, had undergone substantially no discoloration, whereas the untreated gasoline had undergone a decided yellow discoloration.

Phthalic acid, aniline acid phthalate, para A comparison of the aged g'asolines in asuitable color testing apparatus showed that amino phenol acid salt of phthalic acid and the para phenetidine acid salt of phthalic acid have also been incorporated in an unstable cracked gasoline and tested in the manner herein set forth and found to possess desirable color or gum inhibiting properties.

Other quantities of the preferred class of materials than those hereinbefore set forth may be employed. Thus 3 mgs. and 5 mgs. of the preferred class of gum and color inhibitors have been incorporated in 100 c. c. of mineral oil compositions, for' example an unstable gasoline, and

have been found to markedly inhibit the formation of. gum and color therein.

As a further embodiment of the present invention showing the use of the preferred materials in other hydrocarbon fuels than gasoline, 5 and 10 mgs. each of diphenyl guanidine phthalate,

phthalic acid and hexamethylenetetramine acid phthalate were dissolved in 100 c. c. of kerosene and exposed to northern light for varying periods of time and found to possess properties typical ofthe class.

As a further test showing the gum inhibiting properties of the preferred class of materials, the following procedure, which is essentially that described by Egloff, Morrell, Lowry and Dwyer in Industrial and Engineering Chemistry, vol. 24,

pages 1375 to 1382 (1932), was employed;

Into a suitably sized bomb of the type described in the above article, there was placed an 8 ounce oilsample bottle containing 200 c. c. of an un-v stable gasoline, as for example cracking coil distillate to which had been added 20'mgs. of one of the preferred class of materials, for example the paraamino phenol acid salt of phthalic acid. The lid was then placed tightly on the bomb. Substantially one hundred pounds pressure of oxygen was introduced into the bomb by means of a suitable valve. The bomb was then connected, by means of a delivery tube, with a recording pressure gauge, after which it was 'heated in a steam bath until a sharp drop in the pressure curve indicated an end of the period of stability of the unstable fuel, and a rapid reaction of the oxygen with certain unsaturated compounds in the gasoline. The period of stability for the gasoline containing the para amino product, and the solution of the inhibitor thus prepared added thereto.

' Other ratios of the preferred class of materials than those hereinbefore set forth may be employed, also the present invention is applicablev to other mineral oil products than those specifically mentioned, as is readily apparent to those skilled in the art to which this invention pertains.

What is claimed is:

1. A cracked hydrocarbon motor fuel to which has been added a small proportion of a member of a group consisting of diphenyl guanidine phthalate, diphenyl guanidine: acid phthalate, aniline acid phthalate,hexamethylenetetramine acid phthalate, para amino phenol acid salt of phthalic acid and theparaphenetidine acid salt of phthalic acid.

2. Gasoline produced by the cracking of mineral oils to which has been added a small proportion of a member of a group consisting of diphenyl guanidine phthalate, diphenyl guanidine acid phthalate, aniline acid phthalate, hexamethylenetdtramine acid phthalate, para amino phenolacid salt of phthalic acid and-the.

para phenetidine acid salt of phthalic acid.

-3. Gasoline produced by the cracking of mineral oils' to which has been added a smallpro 

